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One big problem with watering at night does not have to do with the grass, but with the system. If you have a broken sprinkler head, it's too dark to evaluate it or diagnose the problem.

Otherwise, with the low humidity in Pho, you should be fine watering DEEPLY, ONCE PER WEEK, when the temps are in the 90s and ONCE EVERY 5 DAYS, when the temps are in the 100s. We call this deep and infrequent watering, and it was developed as a system by a Phoenix based lawn professional. So it works. As the temps cool in the 80s you can back off to once every 2-3 weeks.

Key is you have to water deep when you water. Set out some cat food or tuna cans and time how long it takes to fill them all. Do this in the daylight and confirm it in the night. Water pressure makes a big difference, so if you pressure fluctuates from night to day, you'll have to readjust. Once you have that time, set your sprinkler to water for that time - always. Then the only difference from summer to winter is the frequency with which you turn them on. My oscillator sprinkler takes 8 full hours to fill the cans. My neighbor's high flow in ground system takes 20 minutes. Your system and water pressure are different from everyone else, so you can't go by what your neighbors do.

Watch for runoff when you water. If you see runoff, stop watering immediately and let the water soak in for 15 to 30 minutes. Then resume watering and timing. Sometimes runoff can be a permanent problem. Some people change to low flow sprinkler heads and that works fantastic. Others reschedule their watering to include the soak periods in the schedule. Both approaches work.

You clearly have a problem with water penetration. Try this: spray the lawn with 3 ounces of baby shampoo per 1,000 square feet of lawn. Then water a normal deep water. Next week skip the shampoo and water normally. The week after that, repeat the shampoo treatment with the irrigation. If two treatments of shampoo don't work, you can repeat as often as you like. What the shampoo does is allow the water to penetrate deeper into the soil. Then that deep moisture sets up environmental conditions which restore your soil's beneficial microbes. It is those microbes which allow the water to penetrate into the soil over the long term. Once you get that working, with normal deep, infrequent watering, it should last for years. It doesn't have to be baby shampoo but all baby shampoos work. It can be any clear shampoo with no conditioners or other agents which cloud up the shampoo. I use an ortho hose end sprayer, but any hose end sprayer works.

Wow, great advice. Thank you! I actually just did the cat food test today and one of my areas was only getting about 1/3 of the can full, so I've adjusted that. I will do the shampoo treatment this week and see how that turns out. I actually took a screwdriver around the yard today after the cat food test and I could get it in 6" with a few pounds of force, and while moving it around a bit....not sure if that is cheating or not.

Is Johnson's baby shampoo okay? It is not clear, more of an amber color.

yep should be fine - any brand of baby will do alright.

White Rain or similar at the dollar store or grocery will work also. (cheap)

There are some key ingredients that help more than others. But most have some of them.

With that much standing water and moss growing, it makes me think that is more than a sprinkler head problem and/or soil absorption problem. Is that at the bottom of a hill or heavily shaded area? Is that area consistently wet or damp even when it hasn't been raining or getting watered?

It is in a shaded area, but more or less level with the rest of the yard. A day after it has been watered it is still slightly moist, but certainly not pooled water.

Clear shampoo means any shampoo you can see through. It doesn't matter what color it is as long as you can see through it. You can't see through the ones that have conditioners in them.

Ahhh, got it. Thanks for the clarification!

I've completed two applications of the baby shampoo (with a week of no treatment in between). It has definitely helped in some areas, while other areas seem to still be hard soil. I've noticed that after a couple of inches of penetration with a screwdriver, I can feel gravel in the soil. I dug up a spot and it's not pure gravel by any means, but a few inches down there are a considerable amount of small rocks/stones. Do you think this is negatively affecting my lawn? I've done the tuna can test and adjusted my sprinklers accordingly, but after 4 days of not watering the grass had gotten a bit wilted, so it seems like despite my shampoo treatments the water is still not penetrating deeply enough....? Thoughts? Should I just keep doing the shampoo treatment a few more times? And water slightly more frequently (every 3 days?) until the soil really softens up throughout the yard? There are a lot of brownish spots now (see image below). Mowing once a week about 1.25-1.5" high.

{{!gwi}}

The shampoo treatment sounds interesting and will give it a shot this weekend. But, I'm wondering if this shampoo method will work on flower beds that are hard as rock with hard clay....?

Has anyone tried it?

Yes, and yes it'll work. The initial condition of my soil was unspeakable. Today, post a lot of work, including the equivalent of shampoo (I make my own) it's a joy.

I understand each situation is different, but how many applications should it take? Do you need "maintenance" applications?

It does depend. Using it every 2 weeks, you should notice a difference by the end of October. But if your soil's a real mess, it might take a year to fully transform it.

Post that, two apps a year should maintain it--although if you were also using organics, those two might not be needed.

I still use it, but really don't have to. At this point, it's just insurance.

Well, I did it! The first application of shampoo is in the books. I actually dissolved the 3 oz of shampoo in 8 oz of water and poured that into my hose sprayer, then applied it as evenly as possible and hit it with the sprinklers for almost 30 mins. I'll revert back to my normal watering schedule for the next two,weeks, then do it again. Keeping my fingers crossed!

Well, I did it! The first application of shampoo is in the books. I actually dissolved the 3 oz of shampoo in 8 oz of water and poured that into my hose sprayer, then applied it as evenly as possible and hit it with the sprinklers for almost 30 mins. I'll revert back to my normal watering schedule for the next two,weeks, then do it again. Keeping my fingers crossed!